This invention pertains to the art of chlorine producing devices and more particularly to swimming pool chlorinators.
The invention is particularly applicable to a swimming pool chlorinator which employs a membrane type electrolytic cell and will be described with particular reference to a single monopolar type cell; however, it will be appreciated by those skilled in the art that the invention has broader applications and may find advantageous use in other environments.
Chlorine has been used for some time as a biocidally active agent for use with water in swimming pools. In the past, this has been done largely with chemical treatment of such water by chemical compounds such as a hypochlorite compound. The addition of chemical compounds to effect the biocidal activity desired has become costly and due to restrictions which may be placed upon the traffic of these chemical products, on-site manufacture of such compounds or different means by which such treatment may be carried out must be developed.
Electrochemical methods of manufacture present one solution to this problem due to their capability for small onsite production at a reasonable cost, greater ecological acceptability and potential for energy conservation. Furthermore, electrochemical methods of manufacture can generally be operated as a closed system thereby allowing greater control over the escape of by-products or wastes which may be environmentally undesirable. Improved electrolytic cells which operate at minimum power consumption are especially important because of the rapidly rising price and expected exhaustion of fossil fuels.
A number of types and styles of swimming pool chlorinators utilizing electrolytic cells have heretofore been available for use. However, and even though these prior chlorinators have provided improved results over other known chlorinating systems, they still have had disadvantages in practical application. For example, use has heretofore been made of a swimming pool chlorinator which included an electrolytic cell having a plurality of bipolar electrodes separated by porous asbestos diaphragms. Tests on this type of unit have shown that it is very inefficient in operation and, therefore, has a low production rate of sodium hypochlorite. In addition, such systems suffer from the fact that asbestos particles can be removed from the diaphragm and carried into the swimming pool water. Obviously, this is not desirable and is to be avoided, if possible. Moreover, with some other types of propr chlorinators where the chlorine is injected directly into the pool, the pool owner must dispose of the co-produced sodium hydroxide. This is a corrosive and potentially dangerous chemical.
Further experimental efforts on a small membrane cell showed that this type of cell had good efficiency and chlorine production. Therefore, it was deemed to be exceedingly advantageous to develop an on-site swimming pool chlorinator utilizing a membrane type electrolytic cell for the ultimate generation of sodium hypochlorite. Selective amounts thereof so generated could then be added to the swimming pool water as a biocidally active agent for controlling bacteria and the like therein.